Mercedes-Benz has always been proud of doing almost everything in-house — especially engines. They have a very strong engineering school, lots of proprietary developments, plus AMG, where literally every engine is hand-assembled. But the truth is that not all models are 100% “Mercedes” under the hood. Starting in the 2010s, after the alliance with Renault-Nissan-Mitsubishi, compact classes began to feature shared or purely Renault engines — mainly to save money and meet strict environmental regulations.
Where you definitely get genuine Mercedes engines:
- C-Class (from W206 and older, except the most basic diesels): almost all versions — C 200, C 220, C 300, C 43 AMG and up — use the M254/M264 family (2.0 turbo), M256 (inline-six) or OM654 (diesel). All pure Mercedes, with mild hybrids, excellent response and smoothness.
- E-Class: no question about it — E 200, E 300, E 450, AMG versions. Engines M256, M254, OM654/OM656. Highly praised for quietness, power and hybrid features.
- S-Class (including Maybach): this is elite territory — M176 (biturbo V8), M279 (V12), M256 with electrification. Many are still hand-built in Affalterbach the old-fashioned way: “one man — one engine”.
- G-Class, GLS, GLE, GLE Coupé: OM656 diesels (inline-six), AMG V8 petrols (M177/M178) — all in-house, focused on off-road capability and comfort.
- Any AMG model (A 45, CLA 45, C 63, E 63, GT, SL etc.): M139 (2.0 — still one of the most powerful four-cylinders in the world), M177, M178. Pure AMG, hand-assembled, no compromises.
- SL, GT Roadster, EQS, EQE and large electric models: their own powertrains — either fully electric or hybrid based on M139/M256.
Where you’ll find Renault engines:
In the entry-level classes, to avoid the huge cost of developing small engines and to comply with Euro 6/7, Mercedes uses:
- A-Class: A 180 d / A 200 d — previously pure OM608 (1.5 dCi from Renault), A 200 / A 180 — M282 (1.3 turbo: Renault block + Mercedes head). But since 2021–2022 the diesels are often already the in-house OM654q.
- B-Class, CLA, GLA, GLB: same story — base 180/200 versions (especially diesels and simple petrols) use M282 or OM608. Anything above 200–220 hp is already a proper Mercedes engine.
- Citan and Vito (some versions): 109 CDI, 111 CDI — frequently 1.5 dCi or 1.6 dCi (R9M) straight from Renault.
What’s happening now and going forward:
Mercedes is gradually moving away from Renault. They introduced their own modular FAME family, the OM654q diesel is already replacing the older ones. The 1.3 petrol (M282) still survives in the most basic versions of A/CLA/GLA/GLB, but in top trims and AMG models — only in-house engines. The new CLA and all electric models are already fully on Mercedes platforms.
In short:
C-Class and above, any AMG, G-Class, S-Class or EQS - definitely a Mercedes engine.
In entry-level compact models (A, B, CLA, GLA up to around 200–220 hp) you’ll often find a shared or originally Renault unit, but Mercedes-Benz always refines it and strictly controls quality.